Heeding the Lessons of Obsolescence

Calling a person "obsolete" is bound to hurt his or her feelings. Machinery, on the other hand, isn't sensitive.

In both cases, though, the question of how useful it is to a growing economy is a pressing question. Doves on the Federal Reserve point to a still-large pool of people who remain underemployed, unemployed or able-bodied but officially outside of the labor force. Likewise, industrial-capacity utilization looks...